Hen pecking at back

I have a 10 month old rhode Island red and she just started laying eggs this week. The problem I'm having with her is she started pecking out feathers on an area on her back. She constantly keeps pecking at it to where she has a bald spot about the size of a half dollar. What could it be? Protein deficiency, mites, etc? I have 5 other chickens and nobody else is having that issue except one other who is a little standoffish. But other than that no other problems. I never knew chickens started laying eggs in winter. I have a couple who have never laid and started the last couple weeks.

It sounds like she might have bugs. You should check her over very carefully. You will need to search for mites at night with a flashlight because that's when they are active on the bird. Lice should be visible at any time. Here's a link to help you figure out what you are looking for: